Concealed hinge



A. C. NEILSO N CONCEALED HINGE July 29, 1958 Filed July so, 1956 2 Sheets-Sheet 1 I INVENTORK ALAN c. NEILSON ATTORNEYS F I G--2.

July 29, 1958 A. c. NEILSON 2,844,842

CONCEALED HINGE Filed July so, 1956 2 Sheets-Sheet 2 INVENTOR. ALAN C. NEILSON ATTORNEYS United States 2,844,842 coNcEALEn HINGE Alan C. Neilson, Greenfield, Mass.

Application July 30, 1956, Serial No. 601,044 3 Claims. (Cl. 16-164) This invention relates to new and useful improvements in hinges for doors and the like.

More particularly, the invention relates to a concealed or invisible flat folding hinge and the principal object of the invention is to provide a hinge structure which can be mounted simply and easily on doors and door frames in a variety of ways all without special mortising or any other complex or relatively time consuming operalions.

Another object of the invention is to provide a hinge structure with hinge attaching plates and pivoted hinge leaf members foldable into a thin, flat, narrow, substantially rectangular strip no thicker than its two attachment plates and easily concealed but expendable into a geometrical form capable of supporting a door securely and without sag or play.

A further object of the invention is to provide a 180 opening hinge structure in which the major axes of the two attachment plates always remains parallel and in fixed longitudinal relation during opening or closing movements and the plates and leaves are constrained to follow fixed paths such that at no point in the motion of the hinge are any hinge pins parallel or nearly parallel to the swinging axis of a door to set up a secondary and undesirable pivot point about which the door could swing.

Still further, the invention proposes the construction of a hinge in which the enforced interaction of the members, as constrained by angles at which the hinge pins are set, combine to provide a theoretical pivot point, the locus of which isat all times well outside the silhouette of the hinge when viewed from the top of a vertically mounted hinge.

Other specific objects, advantages and features of the hinge will be apparent from the following description and accompanying drawings.

In the drawings,

Fig. l is an enlarged perspective view of an embodiment of the hinge constructed and arranged in accordance with the present invention and shown in closed or folded position; i

Fig. 2 is a view similar to Fig. l but showing the other side of the hinge;

Fig. 3 is a view of the hinge in fully open position;

Fig. 4 is a full scale edge view of the hinge in closed position; 4 i

Fig. 5 is a side view of the hinge in closed position;

Fig. 6 isa sectional view taken on line 66 of Fig. 5;

Fig. 7 is an enlarged perspective view of the hinge partly opened; p a

Fig. 8 is an enlarged perspective view of the hinge fully opened;

Fig. 9 isatop plan view on the same scale as Figs. 4, 5 and 6 of the hinge mounted on a door and frame assembly (shown in section), the open position of the door and hinge being shown in solidlines and the closed position by dotted outline; and

. Figs. ,1 0 to,17, inclusive, are top plan silhouette views, similarto andon the same scale as Fig. 9., of the hinge as 2,844,842 7 V Patented July 29, 1958 ice 2 mounted on various door and frame assemblies (shown in section), the open positions of the doors and hinges being shown in solid lines and the closed positions by dotted outline, all illustrating applications of the hinge without mortising or other complex operations.

Referring more particularly to the drawings, a hinge is designated generally by the reference numeral 20. It has two thin, flat attachment plates 21 and 22 with spaced countersunk mounting screw holes 27, 28 and 29 provided in both plates 21 and 22. a

Plates 21 and 22 are identical in construction each having a linear inner edge with a substantially triangular leaf connecting portion 33, the leaf connecting sides 34 and 35 of the same being angularly convergent outwardly of the linear edge. Both plates also have a pair of mounting end ears 36 and 37, in which the end mounting holes 27 and 29 are located.

Two opposed pairs of hinged leaves 40, 40 and leaves 41, 41 at their inner or plate connecting ends (inner when the hinge is closed) are respectively secured by angularly disposed hinge pins 44 and 45 to the attachment plates 21 and 22 along the sides 34 and 35. The pairs of leaves 411, 40' and leaves 41, 41' at their outer or leaf connecting ends are pivotally secured together by hinge pins 50. in the closed folded position of the leaves pins 50' are angularly disposed and outwardly divergent relative to each other and to the pins 44 and 45 associated therewith.

Each of the leaves 4%, 40 and 41, 41 is formed along the inner side edge with an arcuate recess 52 intermediate its ends to provide clearance for and receive the adjacent end ears 36 or 37 of plates 21 and 22 when the plates and leaves are brought together in a flat closed position, all as shown by Figs. 1 and 2. 'It will further be noted that the outer edges of the hingeleaves 40, 40 and 41, 41' prefa erably are linearly formed so that inclosed position such edges are generally parallel to the linear inner edges of the plates 21 and 22.

, In this manner each pair of leaves may be pivotally swung on its angularly related pins with the inner or plate ends pivoted in the planes of the attaching plates 21 and 22. .When each pair of leaves 4t), 4t) and 41, 41 is folded together the outer or leaf connecting hinged ends are disposed. beyond the ends of the plates 21 and 22. The plates thus rest together in a fiat flush facing relationship an in a plane with the folded leaves. No part ofthe hinge leaf structure is then of any greater thickness than the two attaching plates. Preferably as shown by Fig. 4 the thickness of the folded plates 21 and 22 is slightly greater than that of the intermediate folded pairs of leaves 40, 40 and 41, 41. it may be noted this dimentional difference will compensate for a slight embedment of plates 21 and 22 in soft wood as when mounted by tightly turned screws and will prevent such embedment' from preventing a proper fiat relation of the in a closed position.

The angles at which the leaves are joined to the plates and at which the two sets of leaves are joined together have a relationship of a more or less critical nature for the preferred symmetrical form and arrangement of the hinge elements and assembled structure. As will become evident from casual inspection of themounting arrangements for the various forms of door and frame connections shown by Figs. 9-17 inclusive, which will be later specifically described, the angular relationship will permit proper dimensional clearances for desired optimum hinge operation in all instances.

Primarily an opening swing of at least a full of the hinge mounting plates is highly desirable. In this way the hinge may be adapted to a maximum number hinge parts of potential installations. Also, the door when fully opened will in the usual case come to rest against a door stop or adjacent wall or door surface rather than be arrested intermediate such position by limitation of the swing of the hinge parts themselves which would leave the door in a position where it might be hit accidentally or otherwise be forced back beyond such intermediate position, thus placing a strain on the hinge and on its mounting screws.

While a full 180 swing is desirable it is also desirable among other considerations to have a compact arrangement of essential elements and an arrangement in which a substantial amount of strength may be built into the parts without making a bulky hinge. It will be appreciated from the form of hinge as thus far described that a compact assembly is shown having an appearance close to that of a conventional hinge and in which the hinge is of a sturdy two plate thickness only, when in closed position. Thus for a given installation a minimum depth of recess for housing the mechanism is needed between a door edge and jamb, and if desired a thinner door or jamb construction may be used. As will be seen the hinge leaves when opened will be fairly flatly disposed against the plates. This means that the leaves are relatively short and do not protrude far into a door opening, hence the hinge is compact in both closed and open positions.

The angles of the pivots 44, 45, and 50 with respect to a vertical pivotal axis of relative movement between the plates are shown with reference to Fig. 5. Specifically in the form shown the angle a is 50 (the angle of pin 44 with said vertical axis), 12 is 60 (the angle between pins 44 or 45 and 50), and c is 70 (the angle of a pin 50 with said vertical axis). Angles in the vicinity of those chosen for illustration of this specific embodiment permit adequate reach (see Fig. 9) of the hinge plates (that is the spacing between the inner facing edges of the plates when fully opened). The arrangement also maintainsadequate lip clearance of at least the thickness of the closed hinge (see Fig. 6). Lip clearance is shown as dimension d in Fig. 9 and is the spacing between the innermost edge portions of the opened hinge leaves and the plane of the outer mounting surfaces of the plates in the open position.

The hinge could be constructed to have a lip clearance of only half the thickness of the closed hinge, but in this event each half of the hinge would have to be recessed equally in door and frame. With the construction shown, one recess and a single lip will conceal the hinge.

Referring again to the angular relationships of the pivotal axes (Fig. each pair of leaves is pivoted at its opposite ends in divergently angled relation with respect to the axis of plate movement so as to form the complementary hinge leaves 40, 40' and 41, 41 as short as possible while maintaining adequate lip clearance and reach.

It will also be noted that the hinge is of a six part construction. Since it has two pairs of leaves it is integrally self-constrained so that the mounting plates 21 and 22 must remain parallel to a common door swing axis, with no relative longitudinal movement along that axis, at any degree of opening. The twisting forces due to door loading which are exerted by the leaves on the pins 44 and 45 are restrained or taken up completely within the mounting plate, so that there is no shearing couple transmitted to the screws as a result of the forces inherent within the hinge structure. Forces acting upon the screws with the six part hinge are the same as exist with an ordinary butt hinge. However, if one pair of leaves were omitted from the structure, then in any except the closed position the forces exerted by the weight of 'a door would'create couples at the plate connecting pins, causing a substantial tendency for the mounting plates to' rotate in the plane of'attachment, and thereby 4 placing an undesirable and unnecessary strain on the screws.

Also the six part hinge of this construction while improving hinge strength may be economically manufactured. It is symmetrical and hence three basic parts only are required. The pair of hinge leaves 40, 40' are respectively identical with leaves 41, 41' and the plates 21 and 22 are identical.

From Figs. 7 and 8 it can be noted that the hinge pins 44, 45, or 50 are never parallel to the axis of relative plate movement from closed to full open position. Thus no secondary axis will be set up for swinging a movable plate member without the hinge elements passing through their intended paths.

As previously stated the angle a may be in the vicinity of 50. If this angle were materially increased, it would necessitate lengthening the leaves 40, 40 and 41, 41. It would also result in approaching near parallelism of pins 44 and 45 at opposite ends of the leaves. In the open or near open position the hinge would be weaker since a slight torsional deflection of the leaves would permit sagging of a door and the leaves would extend well into a door opening. If angle a were materially decreased the size of plates 21 and 22 would need to be unnecessarily large as would also the length of the leaves 40, 40 and 41, 41.

It will be recognized from the geometry of the hinge as shown that a theoretically ideal angular relationship from the standpoint of maximum reach in conjunction with minimum length of leaves alone would mean an angle at a of 45 and at c of 90. However, this condition would means parallelism of pin with the axis of plate move-ment in the 180 open position and no lip clearance in such open position. Consequently the angle a should be increased beyond 45 or the angle at c decreased from or both. Preferably the choice of angles should be such that twice angle a plus angle 0 equals approximately to not as in the case of the above 45 (a) and 90 (0) relation. This will provide a desirable hinge action and avoid a condiion of near parallelism of the leaf pins 50 with the axis of plate swing, and, at the same time will cause removal, in the open 180 position, of the central ends of the leaves from the plane of the plates to provide the lip clearance. By forming the angles such that 2a plus 0 equals approximately 160 to 170, the reach and lip clearance will be sufiicient while at the same time the leaves 40, 40 and 41, 41 may be as short and wide as possible for maximum resistance to torsional deflection and bending and as well for manufacturing economy. Where twice angle a plus c is approximately 160 to 170 there is provided a fairly flatly disposed position of the leaves and an allowance for lip clearance. If the sum of twice angle a plus c is greater than 180 the hinge will not open to 180.

Figs. 9 to 17, inclusive, illustrate a number of typical applications of the hinge without mortising or other complex operation. In Fig. 9 relatively thin flush door 60 and a relatively thin door frame 61 are equipped with a hinge 20 merely by rabbeting or cutting back part of the door only at the edge of the door as indicated at 62.

In Fig. 10 a flush door is provided by mounting a stiffener strip or block 63 on the back of a thin door 64 of plywood or the like and inwardly of its side edge. The attachment plates of the hinge may be secured to the block and to the opposed edge of a door frame 65, without any recessing being required.

In Fig. 11, the hinge is mounted on a flush door 67 but with hinge clearance space at the jamb 68 only instead of the door. This might be used for example in a plywood cabinet, the cabinet side serving as the jamb 68 and no recessing being necessary. A cover strip 69 hides both the end grain and hinge.

In Fig. 12, the hinge is mounted on a flush door 70 with hinge clearance space in both the door and in th jamb71. This installation may be used where a cabinet is to be covered with thin sheeting 7 2 such as metal or plastic. The construction lessens the width of overhang of the thin unsupported material and again no recessing is required.

In Fig. 13, the hinge is mounted in a secret panel type of construction, the door 75 being flush but with a decorative molding 76 overlapping the crack between the door and jam b 77, a simple recess at 78 being provided in the jamb.

In Fig. 14, the hinge is mounted on a door 79 which overlaps the door frame by being secured to a mounting block or stiffener strip 80 fixed to the back of the door and by alsobeing secured to one side of a jam'b 81. This is a simplified construction which allows overlapping at three edges but with corner to corner closure rather than a positive overlap at the hinge edge only. No recessing .is required at the door or jamb.

In Fig. 15, the hinge is mounted on an overlapping door 82 and on a jamb 83 in recesses 84 and 85 in the door and jamb, respectively. No mounting blocks or stiffener strips are required. Only a recess 84 in the door and a recess 85 in the jamb are required.

In Fig. 16, the hinge is mounted on a standard threequarter inch cupboard door 86 having the usual formed edge 87 which overlaps the door opening. This is a standand door construction frequently used in kitchen cabinets. The door 86 and jamb 88 are both provided with simple 30 recessesor bevels at 89 and 90.

In Fig. 17, the hinge is mounted on a door 91 having an overlapping edge at 92 which overlaps the jam'b 93. The jamb is recessed or bevelled at 94 and a stiffener strip or mounting block 95 fixed to the rear of the door may be ripped, bevelled or recessed as at 96 at a 30 angle. The hinge is mounted on the recessed or bevelled edge of the jamb and of the block or stiffener strip.

It will be evident that in all illustrated cases where bevelling or recessing of the door or jamb is stipulated, this recess may be provided at the hinge area only, or may be carried for the full length of the door or jamb as a continuous groove, bevel or recess, as best suits the maker. If carried full length, then only in the construction used in Fig. 15, will any portion of the recess be visible when the door is closed, and then only a small triangular void will be exposed at the top and bottom edge of the door.

The illustrated applications are only some of the many easy and convenient ways the hinge can be applied and indicate the features and advantages of the new hinges discussed above.

What is claimed is:

l. A blind hinge assembly comprising a pair of superposed plates, an upper pair of superposed leaf members hingedly connected together at flieir uppermost ends and respectively hingedly connected to one and the other of said plates at their lower ends, and a lower pair of superposed leaf members hingedly connected together at their lowermost ends and respectively hingedly connected to one and the other of said plates at their upper ends, the axes of the hinged connections of the upper leaf members to said plates being superposed and the corresponding axes of the lower leaf members likewise being superposed, the axes of all the hinged connections of the upper leaf members intersecting a line normal to said supera=the inner angle between the said vertical plane and either of the two pairs of said superposed axes,

c=the outer angle between the said vertical plane and the axis of the said hinged connection between either pair of leaf members,

and

2a+c=less than 180.

2. A blind hinge assembly as in claim 1 wherein,

2a+c=160 to 3. A blind hinge assembly comprising a pair of superposed parallel contacting plates, an upper pair of superposed leaf members hingedly connected together at their uppermost ends at the mid-plane between the members and respectively hingedly connected to one and the other of said plates at their lower ends, said leaf members lying in substantially the same planes as the respective plates to which they are connected, and a lower pair of superposed leaf members hingedly connected together at their lowermost ends at the mid-plane between the members and respectively hingedly connected to one and the other of said plates at their upper ends, said lower leaf members lying in substantially the same planes as the respective plates to which they are connected, said plates terminating short of the hinged connections between the upper leaf members and also short of the hinged connections between the lower leaf members and said leaf members being recessed intermediate their respective ends to provide clearance for attachment portions of said plates, the axes of the hinged connections of the. upper leaf members to said plates being superposed and the corresponding axes of the lower leaf members likewise being superposed, all the axes of the hinged connections of the upper leaf members intersecting a line normal to the planes of said superposed plates and all the axes of the hinged connections of the lower leaf member intersecting a line also normal to the planes of said plates, said lines of intersection defining a vertical plane and with said intersecting axis lines forming the following angular relationships in which:

a=the inner angle between the said vertical plane and either of the two pairs of superposed axes,

c=the outer angle between the said vertical plane and the axis of the hinged connection between either pair of leaf members,

and

2a+c=less than References Cited in the file of this patent UNITED STATES PATENTS 865,895 Hewitt Sept. 10, 1907 1,313,726 Nicol Aug. 19, 1919 1,887,549 Ervin Nov. 15, 1932 2,071,070 Horst Feb. 16, 1937 

